A silver halide photographic material comprises at least one silver halide emulsion layer and at least one non-light-sensitive hydrophilic colloidal layer provided on a support. The silver halide emulsion layer or the hydrophilic colloidal layer often contains a dye, which absorbs a light of a specific wavelength.
A color filter layer is provided on a silver halide emulsion layer to control the spectrum of light incident on the emulsion layer. The filter layer may be provided between two or more emulsion layers. For example, a yellow filter layer is usually provided between a blue sensitive layer and red and green sensitive layers in a multi-layered color photographic material.
An antihalation layer is provided between a support and an emulsion layer or on the backing side of the support. Light incident on an emulsion layer is scattered by the emulsion layer, other layers or a support. The scattered light is reflected at the interface between the support and the emulsion layer or at the backing surface of the support. The scattered and reflected light is incident again on the emulsion layer to cause image blurring, namely halation. The antihalation layer prevents such a problem of halation. The antihalation layer may also be provided between two or more emulsion layers in a multi-layered photographic material.
A silver halide emulsion layer or a hydrophilic colloidal layer may be colored to prevent irradiation, which is caused by scattered light. The irradiation reduces the sharpness of the obtained image.
The above-described layers have been usually colored by fine colloidal silver grains. However, the colloidal silver grains have an adverse influence (e.g., contact fog) on a neighboring silver halide emulsion layer.
Organic dyes have recently been used in place of the colloidal silver to solve the problem. The dyes must satisfy the following conditions:
(1) The dyes have a spectral absorption suitable for their use. PA1 (2) The dyes are inactive chemical compounds in photographic reactions. For example, the dyes should not have adverse chemical effects on silver halide emulsion layers. The adverse effects include reduction of sensitivity, regression of latent image and fog. PA1 (3) The dyes are bleached or dissolved in a processing solution or a washing water. The dyes should not remain in the processed photographic material. PA1 (4) The dyes are not diffused from the dyed layer to the other layers. PA1 (5) The dyes are stable in a solution or in a photographic material. The color formed by the dyes should not be faded nor discolored.
The condition (4) is particularly necessary where the dyes are used in a filter layer or an antihalation layer provided on the side of the emulsion layers. The diffused dyes cause adverse spectral effects on the other layers. Further, the functions of the filter layer or the antihalation layer are degraded by the diffused dyes. However, the dyes tend to be diffused because the colored layer and the other layers are contacted under wet conditions when the layers are formed. Therefore, the photographic materials have been improved to prevent diffusion of the dyes.
For example, Japanese Patent Provisional Publications No. 56(1981)-12639, No. 63(1988)-197943, European Patents No. 15601, No. 274723, No. 299435 and U.S. Pat. No. 4,950,586 disclose a process of forming a colored layer with particles of a solid dye that is insoluble in water.
Further, Japanese Patent Provisional Publications No. 55(1980)-155351, No. 3(1991)-144438, No. 5(1993)-209133, Japanese Patent Publication No. 48(1973)-42175, European Patent Publication No. 524594A and U.S. Pat. No. 4,923,788 disclose dyes preferably used in the form of solid particles. The dyes have a chemical structure wherein an acidic nucleus and a five-membered heterocyclic ring are joined with a methine chain.
Furthermore, Japanese Patent Provisional Publications No. 3(1991)-167546 and No. 5(1993)-86056 disclose photographic dyes comprising a pyrazolone ring and an indole (or pyrrole) ring.